A Review of New Technological Applications in the Use of Sewage Sludge for Sustainable Agriculture

Year 2025, Volume: 9 Issue: Special, 307 - 320, 28.12.2025

Şeyma Akkurt

https://doi.org/10.31015/2025.si.30

Abstract

Sewage sludge from wastewater treatment plants is an important alternative to chemical fertilizers for agricultural use due to its nutrient-rich structure and organic matter content. However, the presence of toxic components (heavy metals, pathogens and persistent organic pollutants) in sewage sludge limits its direct use due to health and environmental risks. Thus, safe processing and effective management techniques are necessary for sludge reuse in agriculture in a sustainable manner. This review examines recent technological advancements that enhance the safe and efficient use of sewage sludge in agriculture. Emphasis is placed on innovative treatment and stabilization methods, such as thermal hydrolysis, anaerobic digestion, and biochar production, which improve nutrient recovery and reduce pathogen and heavy metal risks. Machine learning algorithms are being employed for the real-time prediction of heavy metal concentrations and the overall ecological risk associated with land application. Furthermore, Artificial intelligence (AI) driven soft sensors and optimization models are crucial for controlling operational parameters like sludge retention time, improving process efficiency, and ensuring the final product meets stringent regulatory standards for biosolid application. Ultimately, this review underscores that moving beyond conventional sludge disposal requires integrating cutting-edge recovery technologies with AI-based predictive and control systems to realize a true circular bioeconomy in sludge management.

Keywords

Agriculture , Artificial Intelligence , Environmental Risk , Machine Learning , Sewage Sludge , Sustainability , Wastewater Treatment Plants

References

• Achkir, A., Aouragh, A., El Mahi, M., Lotfi, E. M., Labjar, N., Bouch, M. E., ... & Moussaoui, T. E. (2023). Implication of sewage sludge increased application rates on soil fertility and heavy metals contamination risk. Emerging Contaminants, 9(1), 100200. https://doi.org/10.1016/j.emcon.2022.100200
• Aghanaghad, M., Asgari, E., Sheikhmohammadi, A., & Tajfar, H. (2025). Health risk assessment of heavy metals/metalloid caused by using sewage sludge in agriculture. Desalination and Water Treatment, 321, 100977. https://doi.org/10.1016/j.dwt.2024.100977
• Ahmad, A., Chowdhary, P., Khan, N., Chaurasia, D., Varjani, S., Pandey, A., & Chaturvedi, P. (2022). Effect of sewage sludge biochar on the soil nutrient, microbial abundance, and plant biomass: A sustainable approach towards mitigation of solid waste. Chemosphere, 287, 132112. https://doi.org/10.1016/j.chemosphere.2021.132112
• Alali, Y., Ouda, M., Al-Ali, M., & Al-Nasrallah, B. (2023). Unlocking the potential of machine learning in wastewater treatment: Energy prediction and process optimization. Water, 15(13), 2349. https://doi.org/10.3390/w15132349
• Alloway, B. J., & Jackson, A. P. (1991). The behaviour of heavy metals in sewage sludge-amended soils. Science of the Total Environment, 100, 151-176. https://doi.org/10.1016/0048-9697(91)90377-Q
• Appels, L., Baeyens, J., Degrève, J., & Dewil, R. (2008). Principles and potential of the anaerobic digestion of waste-activated sludge. Progress in Energy and Combustion Science, 34(6), 755–781. https://doi.org/10.1016/j.pecs.2008.06.002
• Arthurson, V. (2008). Proper sanitization of sewage sludge: a critical issue for a sustainable society. Applied and environmental microbiology, 74(17), 5267-5275. https://doi.org/10.1128/AEM.00438-08
• Aydın, M.E., & Aydın, S. 2023. Cleaner Production, Green Deal and Sustainable Waste Management, Micropollutants in Sewerage Sludge and Their. Agricultural Use ISBN: 978-625-8352-57-3
• Baghina, N., Radulov, I., Berbecea, A., Moisuc, A., & Stroia, C. (2014). Sewage sludge fertilisation influence on main soil chemical features. Journal of Environmental Protection and Ecology, 15(1), 217-222.
• Barber, W. P. (2016). Thermal hydrolysis for sewage treatment: a critical review. Water research, 104, 53-71. https://doi.org/10.1016/j.watres.2016.07.069
• Bień, J. D., & Bień, B. (2023). Forecasting the municipal sewage sludge amount generated at wastewater treatment plants using some machine learning methods. Desalination and Water Treatment, 288, 265-272.
• Bravo-Martín-Consuegra, S., García-Navarro, F. J., Amorós-Ortíz-Villajos, J. Á., Pérez-De-Los-Reyes, C., & Higueras, P. L. (2016). Effect of the addition of sewage sludge as a fertilizer on a sandy vineyard soil. Journal of Soils and Sediments, 16(4), 1360-1365. https://doi.org/10.1007/s11368-015-1102-x
• Chang, H., Zhao, Y., Xu, A., Damgaard, A., & Christensen, T. H. (2022). Mini-review of sewage sludge parameters related to system modelling. Waste Management & Research, 41(5), 970-976. https://doi.org/10.1177/0734242X221139171
• Chen, J., Chao, W., Wang, Y., Ren, N., & Lu, L. (2025). Prediction of Waste Sludge Production in Municipal Wastewater Treatment Plants by Deep-Learning Algorithms with Antioverfitting Strategies. ACS ES&T Engineering. https://doi.org/10.1021/acsestengg.5c00100
• Chen, L., Liao, Y., Ma, X., & Lu, S. (2020). Heavy metals chemical speciation and environmental risk of bottom slag during co-combustion of municipal solid waste and sewage sludge. Journal of Cleaner Production, 262, 121318. https://doi.org/10.1016/j.jclepro.2020.121318
• Ching, P. M., So, R. H., & Morck, T. (2021). Advances in soft sensors for wastewater treatment plants: A systematic review. Journal of Water Process Engineering, 44, 102367.
• Clarke, B. O., & Smith, S. R. (2011). Review of “emerging” organic contaminants in biosolids and assessment of international research priorities for the agricultural use of biosolids. Environment International, 37(1), 226–247. https://doi.org/10.1016/j.envint.2010.06.004
• Collivignarelli, M. C., Abbà, A., Castagnola, F., & Bertanza, G. (2017). Minimization of municipal sewage sludge by means of a thermophilic membrane bioreactor with intermittent aeration. Journal of Cleaner Production, 143, 369-376. https://doi.org/10.1016/j.jclepro.2016.12.101
• Cong, R., Oyunchimeg, T., Fujiyama, A., & Matsumoto, T. (2025). How Should AI Technique Support Wastewater Treatment and Sludge Management? A Case Study from Mongolia. In EcoDesign for Circular Value Creation: Volume I (pp. 479-493). Singapore: Springer Nature Singapore.
• Corradini, F., Meza, P., Eguiluz, R., Casado, F., Huerta-Lwanga, E., & Geissen, V. (2019). Evidence of microplastic accumulation in agricultural soils from sewage sludge disposal. Science of the total environment, 671, 411-420. https://doi.org/10.1016/j.scitotenv.2019.03.368
• de Oliveira Paiva, I., de Morais, E. G., Jindo, K., & Silva, C. A. (2024). Biochar N content, pools and aromaticity as affected by feedstock and pyrolysis temperature. Waste and Biomass Valorization, 15(6), 3599-3619.
• Delibacak, S., Voronina, L., & Morachevskaya, E. (2020). Use of sewage sludge in agricultural soils: Useful or harmful. Eurasian Journal of Soil Science, 9(2), 126-139.
• Dikmen, F., Demir, A., Özkaya, B., Raza, M. O., Rasheed, J., Asuroglu, T., & Alsubai, S. (2025). AI-driven wastewater management through comparative analysis of feature selection techniques and predictive models. Scientific Reports, 15(1), 25347.
• Domini, M., Stabile, T., & Masi, S. (2022). Analysis of the variation of costs for sewage sludge transport, recovery and disposal in Northern Italy: a recent survey (2015–2021). Water Science and Technology, 85(4), 1167–1175. https://doi.org/10.2166/wst.2022.040
• Ekinci, E., Özbay, B., Omurca, S. İ., Sayın, F. E., & Özbay, İ. (2023). Application of machine learning algorithms and feature selection methods for better prediction of sludge production in a real advanced biological wastewater treatment plant. Journal of Environmental Management, 348, 119448. https://doi.org/10.1016/j.jenvman.2023.119448
• European Commission. Protection of the Environment, and in particular of the soil, when sewage sludge is used in agriculture. Off. J. Eur. Communities 1986, 4, 6–12.
• Eurostat. (2023). Sewage sludge production and disposal statistics (2022 dataset). https://ec.europa.eu/eurostat/
• Facchini, F., Ranieri, L., & Vitti, M. (2021). A neural network model for decision-making with application in sewage sludge management. Applied Sciences, 11(12), 5434.
• FAO. Agricultural Use of Sewage. In Waste Water Treatment and Use in Agriculture, FAO Irrigation and Drawing Paper 47; Food and Agriculture Organization of the United Nations: Rome, Italy, 1992.
• Feng, J., Burke, I. T., Chen, X., & Stewart, D. I. (2023). Assessing metal contamination and speciation in sewage sludge: Implications for soil application and environmental risk. Reviews in Environmental Science and Bio/Technology. https://doi.org/10.1007/s11157-023-09675-y
• Ferrentino, R., Rossi, G., & Pagliarini, M. (2023). Full-scale sewage sludge reduction technologies and their economic implications. Water, 15(4), 615. https://doi.org/10.3390/w15040615
• Fijalkowski, K., Rorat, A., Grobelak, A., & Kacprzak, M. J. (2017). The presence of contaminations in sewage sludge–The current situation. Journal of environmental management, 203, 1126-1136. https://doi.org/10.1016/j.jenvman.2017.05.068
• Fournie, T., Rashwan, T. L., Switzer, C., & Gerhard, J. I. (2023). Smouldering to treat PFAS in sewage sludge. Waste management, 164, 219-227.
• Fytili, D., & Zabaniotou, A. (2008). Utilization of sewage sludge in EU application of old and new methods—A review. Renewable and Sustainable Energy Reviews, 12(1), 116–140. https://doi.org/10.1016/j.rser.2006.05.014
• Gagliano, E., Sgroi, M., Falciglia, P. P., Vagliasindi, F. G., & Roccaro, P. (2020). Removal of poly-and perfluoroalkyl substances (PFAS) from water by adsorption: Role of PFAS chain length, effect of organic matter and challenges in adsorbent regeneration. Water research, 171, 115381.
• Gherghel, A., Teodosiu, C., & De Gisi, S. (2019). A review on wastewater sludge valorisation and its challenges in the context of circular economy. Journal of cleaner production, 228, 244-263.
• Giwa, A. S., Maurice, N. J., Luoyan, A., Liu, X., Yunlong, Y., & Hong, Z. (2023). Advances in sewage sludge application and treatment: Process integration of plasma pyrolysis and anaerobic digestion with the resource recovery. Heliyon, 9(9). https://doi.org/10.1016/j.heliyon.2023.e19765
• Gogina, E., Makisha, N., & Gulshin, I. (2024). Comparative Analysis of Sewage Sludge Characteristics After Natural Deposition, Accelerated Aging, and Composting. Applied Sciences, 14(22), 10446. https://doi.org/10.3390/app142210446
• Gomes, L. A., Gabriel, N., Gando-Ferreira, L. M., Góis, J. C., & Quina, M. J. (2019). Analysis of potentially toxic metal constraints to apply sewage sludge in Portuguese agricultural soils. Environmental Science and Pollution Research, 26(25), 26000-26014. https://doi.org/10.1007/s11356-019-05796-6
• Gusiatin, M. Z., Kulikowska, D., & Bernat, K. (2024). Municipal sewage sludge as a resource in the circular economy. Energies, 17(11), 2474. https://doi.org/10.3390/en17112474
• Hamdi, H., Hechmi, S., Khelil, M. N., Zoghlami, I. R., Benzarti, S., Mokni-Tlili, S., ... & Jedidi, N. (2019). Repetitive land application of urban sewage sludge: Effect of amendment rates and soil texture on fertility and degradation parameters. Catena, 172, 11-20. https://doi.org/10.1016/j.catena.2018.08.015
• Havukainen, J., Saud, A., Astrup, T. F., Peltola, P., & Horttanainen, M. (2022). Environmental performance of dewatered sewage sludge digestate utilization based on life cycle assessment. Waste Management, 137, 210-221.
• Hu, F., Zhang, X., Lu, B., & Lin, Y. (2024). Real-time control of A2O process in wastewater treatment through fast deep reinforcement learning based on data-driven simulation model. Water, 16(24), 3710. https://doi.org/10.3390/w16243710
• Hudcová, H., Vymazal, J., & Rozkošný, M. (2019). Present restrictions of sewage sludge application in agriculture within the European Union. Soil & Water Research, 14(2).
• Iticescu, C., Georgescu, L. P., Murariu, G., Circiumaru, A., & Timofti, M. (2018, November). The characteristics of sewage sludge used on agricultural lands. In AIP conference proceedings (Vol. 2022, No. 1, p. 020001). AIP Publishing LLC.
• Kacprzak, M., Neczaj, E., Fijałkowski, K., Grobelak, A., Grosser, A., Worwag, M., ... & Singh, B. R. (2017). Sewage sludge disposal strategies for sustainable development. Environmental research, 156, 39-46. https://doi.org/10.1016/j.envres.2017.03.010
• Kelessidis, A., & Stasinakis, A. S. (2012). Comparative study of the methods used for treatment and final disposal of sewage sludge in European countries. Waste Management, 32(6), 1186–1195. https://doi.org/10.1016/j.wasman.2012.01.012 https://doi.org/10.1016/j.wasman.2012.01.012
• Kim, D., Hadigheh, S. A., & Wei, Y. (2024). Unlocking biosolid pyrolysis: Towards tailored biochar with different surface properties. Materials Today Sustainability, 27, 100868.
• Kim, J. K., Dooley, M., Lee, M. H., & Lee, J. M. (2019). Activated sludge process diagnosis using advanced real-time monitoring equipment: activated sludge plant controller (ASP-CON). Environmental Earth Sciences, 78(15), 448. https://doi.org/10.1007/s12665-019-8444-4
• Lamastra, L., Suciu, N. A., & Trevisan, M. (2018). Sewage sludge for sustainable agriculture: contaminants’ contents and potential use as fertilizer. Chemical and Biological Technologies in Agriculture, 5(10), 1-6. https://doi.org/10.1186/s40538-018-0122-3
• Latare, A. M., Kumar, O., Singh, S. K., & Gupta, A. (2014). Direct and residual effect of sewage sludge on yield, heavy metals content and soil fertility under rice–wheat system. Ecological engineering, 69, 17-24. https://doi.org/10.1016/j.ecoleng.2014.03.066
• Li, J., Wu, Y., Li, D., Tang, P., Zhang, W., Zhao, Q., ... & Peng, Y. (2024). Combined effect of thermal hydrolysis process and low-temperature pyrolysis on the classification and bioavailability of phosphorus in sewage sludge. Bioresource Technology, 407, 131135. https://doi.org/10.1016/j.biortech.2024.131135
• Liu, H., Wang, Z., Nghiem, L. D., Gao, L., Zamyadi, A., Zhang, Z., ... & Wang, Q. (2021). Solid-embedded microplastics from sewage sludge to agricultural soils: Detection, occurrence, and impacts. ACS ES&T Water, 1(6), 1322-1333. https://doi.org/10.1021/acsestwater.0c00218
• Loutfy, N., Fuerhacker, M., Tundo, P., Raccanelli, S., El Dien, A. G., & Ahmed, M. T. (2006). Dietary intake of dioxins and dioxin-like PCBs, due to the consumption of dairy products, fish/seafood and meat from Ismailia city, Egypt. Science of the total environment, 370(1), 1-8.
• Lucia, C., Badalucco, L., Corsino, S. F., Galati, A., Iovino, M., Muscarella, S. M., ... & Laudicina, V. A. (2025). Management and valorisation of sewage sludge to foster the circular economy in the agricultural sector. Discover Soil, 2(1), 80. https://doi.org/10.1007/s44378-025-00105-9
• Manea, E. E., & Bumbac, C. (2024). Sludge Composting—Is This a Viable Solution for Wastewater Sludge Management?. Water (20734441), 16(16).
• Melo, W., Delarica, D., Guedes, A., Lavezzo, L., Donha, R., de Araújo, A., ... & Macedo, F. (2018). Ten years of application of sewage sludge on tropical soil. A balance sheet on agricultural crops and environmental quality. Science of the total environment, 643, 1493-1501. https://doi.org/10.1016/j.scitotenv.2018.06.254
• Meservey, A., Külaots, I., Bryant, J. D., Gray, C., Wahl, J., Manz, K. E., & Pennell, K. D. (2024). Adsorption of per-and polyfluoroalkyl substances on biochar derived from municipal sewage sludge. Chemosphere, 365, 143331.
• Nasir, F. B., & Li, J. (2024). Understanding machine learning predictions of wastewater treatment plant sludge with explainable artificial intelligence. Water Environment Research, 96(10), e11136. https://doi.org/10.1002/wer.11136
• Nunes, N., Ragonezi, C., Gouveia, C. S., & Pinheiro de Carvalho, M. Â. A. (2021). Review of sewage sludge as a soil amendment in relation to current international guidelines: A heavy metal perspective. Sustainability, 13(4), 2317. https://doi.org/10.3390/su13042317
• Olaniran, A. O., Balgobind, A., & Pillay, B. (2013). Bioavailability of heavy metals in soil: impact on microbial biodegradation of organic compounds and possible improvement strategies. International journal of molecular sciences, 14(5), 10197-10228.
• Panahi, A., Bakhtiari, V., Piadeh, F., & Behzadian, K. (2025). A systems-based approach to circular sludge management: Data-driven foresight, sustainability assessment, and strategic evaluation. Journal of Environmental Management, 392, 126615. https://doi.org/10.1016/j.jenvman.2025.126615
• Polito-Braga, C. M., Von Sperling, M., Braga, A. R., & Pena, R. T. (2002). Real time control of a combined UASB-activated sludge wastewater treatment configuration. Water science and technology, 45(4-5), 279-287. https://doi.org/10.2166/wst.2002.0605
• Qiu, C., Li, J., Wang, C., Liu, N., Qi, L., Wang, D., ... & Sun, L. (2023). Transformation and environmental risk of heavy metals in sewage sludge during the combined thermal hydrolysis, anaerobic digestion and heat drying treatment process. Environmental Science and Pollution Research, 30(18), 54234-54241. https://doi.org/10.1007/s11356-023-26200-4
• Rulkens, W. (2008). Sewage sludge as a biomass resource for the production of energy: overview and assessment of the various options. Energy & Fuels, 22(1), 9-15. https://doi.org/10.1021/ef700267m
• Salva, J., Sečkár, M., Schwarz, M., Samešová, D., Mordáčová, M., Poništ, J., & Veverková, D. (2025). Analysis of the current state of sewage sludge treatment from the perspective of current European directives. Environmental Sciences Europe, 37(1), 1-27. https://doi.org/10.1186/s12302-025-01097-7
• Sandrin, T. R., & Hoffman, D. R. (2007). Bioremediation of organic and metal co-contaminated environments: effects of metal toxicity, speciation, and bioavailability on biodegradation. In Environmental bioremediation technologies (pp. 1-34). Berlin, Heidelberg: Springer Berlin Heidelberg.
• Shabir, R., Li, Y., Megharaj, M., & Chen, C. (2024). Pyrolysis temperature affects biochar suitability as an alternative rhizobial carrier. Biology and Fertility of Soils, 60(5), 681-697.
• Shao, S., Fu, D., Yang, T., Mu, H., Gao, Q., & Zhang, Y. (2023). Analysis of machine learning models for wastewater treatment plant sludge output prediction. Sustainability, 15(18), 13380. https://doi.org/10.3390/su151813380
• Shi, Y. X., Wu, S. H., Zhou, S. L., Wang, C. H., & Chen, H. (2016). Simulation of the absorption, migration and accumulation process of heavy metal elements in soil-crop system. Huan jing ke xue= Huanjing kexue, 37(10), 3996-4003. https://doi.org/10.13227/j.hjkx.2016.10.043
• Shirkoohi, M. G., Tyagi, R. D., Vanrolleghem, P. A., & Drogui, P. (2022). A comparison of artificial intelligence models for predicting phosphate removal efficiency from wastewater using the electrocoagulation process. Digital Chemical Engineering, 4, 100043.
• Shojaei, S., Jafarpour, A., Shojaei, S., Gyasi-Agyei, Y., & Rodrigo-Comino, J. (2021). Heavy metal uptake by plants from wastewater of different pulp concentrations and contaminated soils. Journal of Cleaner Production, 296, 126345. https://doi.org/10.1016/j.jclepro.2021.126345
• Shyu, H. Y., Castro, C. J., Bair, R. A., Lu, Q., & Yeh, D. H. (2023). Development of a soft sensor using machine learning algorithms for predicting the water quality of an onsite wastewater treatment system. ACS Environmental Au, 3(5), 308-318.
• Singh, D. K. (2024). Thermal hydrolysis of sewage sludge: Improvement in digestibility and nutrient recovery. Waste Management & Research, 42(1), 51-58. https://doi.org/10.1177/0734242X231171044
• Singh, R. P., & Agrawal, M. (2010). Variations in heavy metal accumulation, growth and yield of rice plants grown at different sewage sludge amendment rates. Ecotoxicology and Environmental Safety, 73(4), 632-641. https://doi.org/10.1016/j.ecoenv.2010.01.020
• Spanos, T., Gidarakos, E., Li, X., & Voudrias, E. A. (2016). Temporal variability of sewage sludge heavy metal content from Greek wastewater treatment plants. Ecological Chemistry and Engineering S, 23(2), 271–283. https://doi.org/10.1515/eces-2016-0019
• Spinosa, L., Ayol, A., Baudez, J. C., Canziani, R., Jenicek, P., Leonard, A., ... & Van Dijk, L. (2011). Sustainable and innovative solutions for sewage sludge management. Water, 3(2), 702-717.
• Stoiber, T., Evans, S., & Naidenko, O. V. (2020). Disposal of products and materials containing per-and polyfluoroalkyl substances (PFAS): A cyclical problem. Chemosphere, 260, 127659.
• Tan, Y. Y., Huong, Y. Z., Tang, F. E., & Cheng, C. Y. (2024). A review of sewage sludge dewatering and stabilisation in reed bed systems: Towards process-based modelling. International Journal of Environmental Science and Technology, 21, 997–1020. https://doi.org/10.1007/s13762-023-05063-9
• Tarpani, R. R. Z., Alfonsín, C., Hospido, A., & Azapagic, A. (2020). Life cycle environmental impacts of sewage sludge treatment methods for resource recovery considering ecotoxicity of heavy metals and pharmaceutical and personal care products. Journal of Environmental management, 260, 109643.
• Tchobanoglous, G., Burton, F. L., Stensel, H. D., Tsuchihashi, R., & Abu-Orf, M. (2014). Wastewater Engineering: Treatment and Resource Reuse (5th ed.). McGraw-Hill Education.
• TUIK, 2023 Turkish Statistical Institute Newsletter, https://data.tuik.gov.tr/Bulten/Index?p=Atik-Istatistikleri-2022-49570. 21.10.2025
• Tytła, M., Widziewicz, K., & Zielewicz, E. (2016). Heavy metals and its chemical speciation in sewage sludge at different stages of processing. Environmental Technology, 37(7), 899-908.
• U.S. Environmental Protection Agency (EPA). (2025a). Chemicals in sewage sludge fertilizer pose cancer risk, EPA says. AP News. https://apnews.com/article/42e084b6a41852fdafd199d355c7a890
• U.S. Environmental Protection Agency (EPA). (2025b). Risk assessment of pollutants in sewage sludge. EPA. https://www.epa.gov/biosolids/risk-assessment-pollutants-sewage-sludge
• U.S. Environmental Protection Agency. (2022). Biosolids Biennial Report No. 9 (Reporting Period 2020–2021) — Fact Sheet. https://www.epa.gov/system/files/documents/2022-12/2020-2021-biennial-factsheet.pdf
• Vadenbo, C., Guillén-Gosálbez, G., Saner, D., & Hellweg, S. (2014). Multi-objective optimization of waste and resource management in industrial networks–Part II: Model application to the treatment of sewage sludge. Resources, Conservation and Recycling, 89, 41-51.
• Vali, N., Zabihi, S., Shamim, S., Mohsenzadeh, A., & Pettersson, A. (2025). Slow-pyrolysis of municipal sewage sludge: Biochar characteristics and advanced thermodynamics. Biomass Conversion and Biorefinery, 15, 21045–21065. https://doi.org/10.1007/s13399-025-06680-9
• Voipan, D., Voipan, A. E., & Barbu, M. (2025). Evaluating machine learning-based soft sensors for effluent quality prediction in wastewater treatment under variable weather conditions. Sensors (Basel, Switzerland), 25(6), 1692.
• Wang, J., & Tomita, A. (2003). A chemistry on the volatility of some trace elements during coal combustion and pyrolysis. Energy & fuels, 17(4), 954-960.
• Wang, Y., Cheng, Y., Liu, H., Guo, Q., Dai, C., Zhao, M., & Liu, D. (2023). A review on applications of artificial intelligence in wastewater treatment. Sustainability, 15(18), 13557. https://doi.org/10.3390/su151813557
• Wei, Y., & Liu, Y. (2005). Effects of sewage sludge compost application on crops and cropland in a 3-year field study. Chemosphere, 59(9), 1257-1265. https://doi.org/10.1016/j.chemosphere.2004.11.052
• Xiao, D., Li, H., Wang, Y., Wen, G., & Wang, C. (2023). Distribution characteristics of typical heavy metals in sludge from wastewater plants in Jiangsu Province (China) and their potential risks. Water, 15(2), 313. https://doi.org/10.3390/w15020313
• Yakamercan, E., Ari, A., & Aygün, A. (2021). Land application of municipal sewage sludge: Human health risk assessment of heavy metals. Journal of Cleaner Production, 319, 128568. https://doi.org/10.1016/j.jclepro.2021.128568
• Yalcin, S., & Ayyildiz, E. (2024). Analyzing the impact of artificial intelligence on operational efficiency in wastewater treatment: A comprehensive neutrosophic AHP-based SWOT analysis. Environmental Science and Pollution Research, 31(38), 51000-51024.
• Yıldız, S. & Olabi A. (2021) Treatment Sludge Disposal Methods and Recent Developments, World Environment Day Symposium. 09.06.2021 Sivas,Türkiye
• Yu, J., & Li, G. (2024). Evaluating Artificial Intelligence-Based Industrial Wastewater Anaerobic Ammonium Oxidation Treatment Optimization and Its Environmental, Economic, and Social Benefits Using a Life Cycle Assessment–System Dynamics Model. Processes, 13(1), 59.
• Zhang, W., Jiang, T., & Liang, Y. (2022). Stabilization of per-and polyfluoroalkyl substances (PFAS) in sewage sludge using different sorbents. Journal of Hazardous Materials Advances, 6, 100089.
• Zhang, X., Ma, G., Chen, T., Yan, C., Chen, Y., Wang, Q., ... & Kong, Z. (2024). Towards carbon-neutral biotechnologies for rural wastewater: A review of current treatment processes and future perspectives. Journal of Water Process Engineering, 58, 104773. https://doi.org/10.1016/j.jwpe.2024.104773
• Zhao, L., Sun, Z.-F., Pan, X.-W., Tan, J.-Y., Yang, S.-S., Wu, J.-T., Chen, C., Yuan, Y., & Ren, N.-Q. (2023). Sewage sludge derived biochar for environmental improvement: Advances, challenges, and solutions. Water Research X, 18, 100167. https://doi.org/10.1016/j.wroa.2023.100167
• Zhou, G., Gu, Y., Yuan, H., Gong, Y., & Wu, Y. (2020). Selecting sustainable technologies for disposal of municipal sewage sludge using a multi-criterion decision-making method: A case study from China. Resources, Conservation and Recycling, 161, 104881. https://doi.org/10.1016/j.resconrec.2020.104881
• Zhou, H., Yang, W. T., Zhou, X., Liu, L., Gu, J. F., Wang, W. L., ... & Liao, B. H. (2016). Accumulation of heavy metals in vegetable species planted in contaminated soils and the health risk assessment. International journal of environmental research and public health, 13(3), 289.
• Zhou, J., Chen, J., Zhang, W., Tong, Y., Liu, S., Xu, D., ... & Li, H. (2025). Machine-learning-aided life cycle assessment and techno-economic analysis of hydrothermal liquefaction of sewage sludge for bio-oil production. Energy, 319, 135026.
• Zhuang, P., McBride, M. B., Xia, H., Li, N., & Li, Z. (2009). Health risk from heavy metals via consumption of food crops in the vicinity of Dabaoshan mine, South China. Science of the total environment, 407(5), 1551-1561.
• Zorpas, A., & Inglezakis, V. J. (2012). Sewage sludge management: From the past to our century. Nova Science Publishers, Inc. 1-511.
• Zuloaga, O., Navarro, P., Bizkarguenaga, E., Iparraguirre, A., Vallejo, A., Olivares, M., & Prieto, A. (2012). Overview of extraction, clean-up and detection techniques for the determination of organic pollutants in sewage sludge: a review. Analytica chimica acta, 736, 7-29.